The LM25180 is a 42Vin Opticless Flyback Converter with 65V, 1.5A Integrated MOSFET

The LM25180 is a primary-side regulated (PSR) flyback converter with high efficiency over a wide input voltage range of 4.5V to 42V. The isolated output voltage is sampled from the primary-side flyback voltage without the need for an optocoupler, voltage reference, or tertiary winding from the AD5392BCPZ-3 transformer for output voltage regulation.

The high level of integration enables a simple, reliable and high-density design with only one component passing through the isolation barrier. Boundary Conduction Mode (BCM) switches enable compact magnetic solutions and better than ±1.5% load and line regulation. An integrated 65V power MOSFET delivers up to 7W of output power with enhanced headroom for line transients.

The LM25180 flyback converter is available in an 8-pin, 4mm × 4mm, thermally enhanced WSON package with 0.8mm lead pitch.

The LM25180 flyback converter simplifies the implementation of isolated DC/DC power supplies and has optional features to optimize the performance of the target end equipment. The output voltage is set by a resistor, and an optional resistor improves output voltage accuracy by canceling the thermal coefficient of the flyback diode drop. Additional features include internally fixed or externally programmable soft-start, optional bias supply connection for improved efficiency, precision enable input with hysteresis for adjustable line UVLO, hiccup mode overload protection, and thermal with automatic recovery Shutdown protection.


●Designed for reliable and rugged applications

○Wide input voltage range of 4.5 V to 42 V, operating down to 3.5 V after startup

○ Robust solution where only one component crosses the isolation barrier

○±1.5% total output adjustment accuracy

○ Optional V OUT temperature compensation

○6ms internal or programmable soft-start

○Input UVLO and thermal shutdown protection

○Hiccup mode overcurrent fault protection

○–40°C to +150°C Junction Temperature Range

● Integration reduces solution size and cost

○Integrated 65V, 0.4Ω power MOSFET

○ V OUT regulation requires no optocoupler or transformer auxiliary winding

○Internal loop compensation

●Efficient PSR flyback operation

○ Quasi-resonant MOSFET in BCM turns off

○ Low input quiescent current

○ External bias option for increased efficiency

○Single output and multiple output implementation

●Ultra low conducted and radiated EMI characteristics

○ Soft switching avoids diode reverse recovery

○Optimized for CISPR 32 EMI requirements

●Create custom regulator designs with WEBENCH® Power Designer


●Isolated field transmitter and field actuator

●Multiple output rails for analog input modules

Motor drive: IGBT and SiC gate drive power supply

●Building automation HVAC system

●Isolated bias supply


Input Voltage (Max) (V): 42

Input Voltage (Min) (V): 4.5

Output (Max) (A): 1.5

Features: UVLO adjustable, enable, integrated switch, light load efficiency, pre-bias start-up

Operating temperature range (°C): -40 to 150

Adjust output (#): 1

Packaging Type: WSON

TI Functional Safety Category: Functional Safety Capability

◆ Typical application of LM25180

LM25180 functional block diagram